changing the AHB Matrix priorities

[ankish_kacktwan]

How can we change the AHB Matrix priorities in lpc1779 device?

[ZhangJennie]

LPC177x has Matrix Arbitration register
The Matrix Arbitration register provides the ability to change the default AHB Matrix arbitration priorities.

Please see MATRIXARB in UM.

Have a great day,
Jun Zhang

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[ankish_kacktwan]

can it be changed for LPC1778 device as well 

because i can not see any MATRIXARB register in LPC177x_8x.h

[ZhangJennie]

According to UM, Matrix Arbitration register physically exists in LPC177x/8x. 

I check one of lpcopen, lpcopen_2_10_lpcxpresso_ea_devkit_1788, MATRIXARB is defined in sysctl_17xx_40xx.h.

if your project don't have it, you can define it as below:

#define MATRIX_ARB  (*(volatile U32*)(0x400FC188))
  MATRIX_ARB = 0            // Set AHB Matrix priorities [0..3] with 3 being highest priority
               | (1 <<  0)  // PRI_ICODE : I-Code bus priority. Should be lower than PRI_DCODE for proper operation.
               | (3 <<  2)  // PRI_DCODE : D-Code bus priority.
               | (0 <<  4)  // PRI_SYS   : System bus priority.
               | (0 <<  6)  // PRI_GPDMA : General Purpose DMA controller priority.
               | (0 <<  8)  // PRI_ETH   : Ethernet: DMA priority.
               | (3 << 10)  // PRI_LCD   : LCD DMA priority.
               | (0 << 12)  // PRI_USB   : USB DMA priority.
              ; 
  //MATRIX_ARB = 0x00000C09;‍‍‍‍‍‍‍‍‍‍‍

Have a nice day,

Jun Zhang